Machine gun



vB. PUTNAM.

MACHINE GUN. APPLICATION FILED AUG.30, I917.

Patented Sept. 19, 1922.

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B. PUTNAM.

MACHINE GUN.

APPLICATION FILED AUG-30, 1911.

Patented Sept. 19, 1922.

4 SHEETS-SHEET 3- B. PU TNAM. I MACHINE GUN. APPLICATION FILED AUG. 30' I917- 'Patgnted Sept. 19

4 SHEETS-SHEET 4.

/7 Ema/7 Eur/ tendency Patented Sept. 1 9, 1922.

BURLEIGH PUTNAM, 0F PASADENA, CALIFORNIA.

MACHINE GUN.

Application filed August 30, 1917. Serial No. 188,921.

To all whom it may concern:

Be it known that I, BURLEIGH PUTNAM, a citizen of the United States, residing at Pasadena, in the county of Los Angeles, State of California, have invented a new and useful Improvement in Machine Guns, of which the following is a specification.

My invention relates to firearms which are arranged to fire consecutively when once started until-they are either stopped by the gurlmer or until thesupply of ammunition fai s.

The principal object of my invention is to produce a gun which shall be positive in operation, WlllCh shall'have few parts,'and which shall be light inweight and inexpensive to construct.-

These objects are accomplished by the use of a reciprocating barrel which is blown or pulled forward by the explosion of the cartridge and by the use of cartridges which are mounted in sets often or more in a clip in which they are fired and in which they are fed into the gun as a unit. I

As the cartridge shells are ordinarily formed of light sheet brass they expand in the barrel duringthe' time of the explosion due to the high pressure of the gases therein at that time and they therefore tend to grip the chamber of the barrel in which they are fired and thereby prevent the forward movement of the barrel. It is a further object of my invention to provide an oiling device which shall form a part of the gun and b means of which the shells shall be l7(l1l0I011g ly lubricated just before they are fire I have fouhd that while there is a strong for the barrel to move forward as the cartridge is discharged that this force under some conditions and with some charges is insuificient to start the barrel especially where the shellsare partly or in-' sufliciently lubricated. It is a further object of 'my invention to provide an actuator which is operated by the gases of the explosion and which is so arranged that the barrel is moved forward with considerable force at the moment of the explosion.

In some types of guns it is suflicient to provide clips containing from ten to thirty shells and to provide for hand reloading of the gun after each clip is fired. In other types of" gun it is desirable to provide for firing a much larger number of shells without reloading. It is a further object of my attempt to get high speed having invention to provide a magazine which shall hold anumber of clips and to provide a mechanism by which these clips are automatlcally fed into the gun in order and fired consecutively.

A further object of my invention is to provide a novel form of clip in which the standard United States Army ammunition maybe loaded. This ammunition has the head of the shell the same diameter as the body, the head being separated from the body andin reality formed b an extractor groove formed in the body 0 the shell and of somewhat smaller diameter at its base than the diameter of the body.

A still further object of my invention is to provide a novel form of magazine in which a plurality of clips may be mounted and in which they can be readily loaded and transported and in which they may be placed in such relation to'the gun that they can be readily fed thereto.

I have found that it is desirable to load the magazines with fifty rounds which may be made up of ten clips of five shells each or preferably of five clips of ten rounds each and such a magazine with its load will weigh about four pounds. To reduce the labor of handling I have devised a container which will take twelve magazines and which will weigh loaded about fifty pounds. This container I make in cylindrical form so that it is compact and may be easily rolled about to save lifting.

As guns made according to my system are very compact and are very positive in their actlon due to the large forces available for their actuation they are inclined to shoot very fast, a model gun made without any fired over twelve hundred shots a minute. As a high speed is in most cases desirable in a machine gun this is not a disadvantage in the case of my invention but there are some cases in which a lower speed is desired. A further object of my invention is to provide means by which the gun-can be so constructed as to materially reduce its natural highspeed. This I accomplish by what I call a retarder.

The United States Army demands and it' seems desirable to build two types of machine guns known as the light type and the heavytype respectively. In the heavy type a water jacket may be used around the barrel for the purpose of coolino it, but in the light type gun the weight of the jacket ment is considerable, being about four inches.

Further objects and advantages will be made evident hereinafter or will be evident to one skilled in the machine gun art after an inspection of the accompanying drawings and a perusal of the following specification.

In the drawings which are some-what diagrammatic,

Fig. 1 is a side elevation of the muzzle end of a machine-gun embodying my invention, a portion thereof being shown in section to better illustrate the novel features thereof.

Fig. 2 is a similar view of the breech end of the same gun the stock of which is shown broken away as stocks are old in the'art and form no portion of the present inven tion. The gun shown in Figs. 1 and 2 is in the open or cooked position.

Fig. 3 is a plan view loo-king down on the top of the gun, portions thereof being broken away or shown in section and portions beyond the immediate foreground being omitted for the purpose of making the spirit of the invention plain. In this view the gun is shown in its cocked position witha maigazine in place.

ig. 4 is a section of the gun in its closed position on a broken plane indicated by the line 4'4 of Fig. 2,,this plane being viewed in the direction of the arrows. I

Fig. 5 is a section of the gun in its closed position on a plane indicated by the line 5-5 of Fig. 4, this plane being viewed in.

the direction of'the arrows.

Fig. 6 is a section on a plane indicated by the line 6-6 of Fig. 4 this plane being viewed in the direction of the arrows.

Fig. is a sectional elevation of one of the feed dogs shown on an enlarged scale from the previously described views.

Fig. 8 is a perspective view on an enlarged scale of a portion of one form.- of clip.

Fig. 9 is a section through the same clip with' a standard Springfield cartridge in place therein. a r

Fig. 10 is a front view of a portion of the form of clip shown in Fig. 9.

Fig. 11 is a front view of a portion of an alternate form of clip.

Fig. 12 is a section on a plane indicated by the line 1212 of Fig. 11.

Fig. 13 is a side elevation viewed from the gun side of a magazine carrier and magazine in place therein.

F ig. 14 is a perspective view of an empty magazine.

Fig. I5 is a plan view of a container broken away to show how the magazines fit therein and how the .clips fit in the magazines.

Fig. 16 is a side elevation of the'container shown in Fig. 15 similarly broken away.

Fig. 17 is a sectional side elevation of one form of air cooling device.

Fig. 18 is an end view of the parts shown in Fig. 17.

Fig. 19 is a section on a plane indicated by the line 19--19 of Fig. 17.

Fig. 20 is a sectional side elevation of an alternate form of air cooling device.

Fig. 21'is a section on a plane indicated by the line 21-21 of Fig. 20.

Fig. 22 is an end view of the parts shown in Fig. 20.

In the form of my invention-shown in the drawings a main frame 31 is provided with any desired form of well known stock not shown which may be attached to the frame 31 at 32. Mounted in a back guide 33 and a front guide 34 is a barrel 35 which is free to move forward from its firing posi-' tion in which it abuts against a solid breech block 36 which forms anintegral part of the frame 31.- Threaded or otherwise secured in the front support or. forward guide 34 is a bearing member 37 in which the barrel slides.- Threaded or otherwise secured to the muzzle end of the barrel 35 is an actuator piston 38 which fits closely into an actuator cylinder 39 formed in the front end of the bearing 37. Formed on the barrel 35 are a series of cooling ribs 40 the front one 41 of which is somewhat elongated and forms a retarding piston which fits closely in a retarding cylinder 42 formed in the rear end of the bearing 37. A small port 43 formed in the barrel 35 just back of the actuator piston, 38 serves as a gas vent to pass the gases of the explosion into the gas cylinder 39 back of the actuator piston 38 when the gun is in the firing position so that these gases in expandin can force the barrel 35 forward from,- the rlng position. A small vent port 44 formed in the bearing 37 serves to permit the air compressed by the retarding piston 41 in the retarding cylinder 42 to escape as the piston '41 is driven home and also serves to allowair to enter the cylinder 42 as the barrelis forced back thus relieving the partial vacuum formed thereln by the recession cf the piston 41.

Threaded or otherwise secured to the barrel 35 is a nut 50 which is such a shape and size that it fits closely into an open sided box formed at the rear of the main frame 31 by a top 51, a back 52, and a bottom 53, all of which are preferably machined to fit closely about the nut 50. Secured to the nut 50 is an operating handle 54 which projects out to one side of the gun in a convenient position to be grasped by the gunner for the purpose of manually actuating the barrel 35.

Secured in the back guide 33 and the front gu1de'34 is a spring tube 55 which contains an operating spring 56. This spring .is of the compression type and presses at one end on the, closed front of the tube 55 and at its other end on the front of 'the nut 50. In actual practice the spring 56 is quite strong and tendsto throw the nut 50 and the. barrel 35 backward towards the breech bloekg36 in the direction of the arrow 57 shown in Fig. 1. For the purpose of holding the gunin its open or cocked position a sear 58 is provided as shown in Fig. 2. The sear 58 1S pivoted on a pin 59 and is made integral with a trigger 60, being held in its engaged position by a light compression spring 61. A trigger guard 63 is provided which may conveniently connect to a pistol grip 64 formed or securedto the bottom-53 of the frame 31. s

For the purpose of retaining the nut 50 in the box formed by the parts 51, 52, and 53, a guide 65 may be used this guide being of a T section and projecting through an open slot in the top 51 down into a slot formed in the top of the nut 50.

The standard form of cartridge now used by the United States Army and known as tion groove the Springfield has a head about the same diameter as the body as shown in Fig. 9. One form of clip suited to hold such cartridges is shown in Fig. 8 and consists of a sheet of metal bent into a channel section having a web 70, and two flanges 71. Cut in the web 7 0 are a plurality of open slots 72 which have a wldth corresponding to the diameter of the bottom of the extrac- 73 of the standard shell 74. One flange 71 of the clip 75 is also cut away to allow the head of the shell 74 to pass. In practicethe shells 74 are forced into the slots 72 by an automatic loading" machine which forms no part of the present invention and is therefore not illustrated. ,The

clips are made of material of about the same thickness as the width of the extraction groove 73 and if properly loaded the cartridges are firmly anchored in the clips so that they will not be'jarred out in shipment. It is not necessaryl for the successful operation of the gun that the shells be accurately placed as the bullets are tapered to a fine point and the barrel will cause the bullet to enter even if the shell be somewhat out of line and once entered the barrel 82, the other end being Other forms of clip may be used. For example in Fig. 10 I show a modified form of clipin which small spring ears 77 are punched out of the material from which the clip is formed so that the clip is securely held in place about the shell 74.

In Figs. 11 and 12 I show still another form of clip in whicha hole is first punched in the clip of the proper size to fit around the shell at the bottom of the extractor groove 73 and small radial cuts are then made extending out from the hole which is sprung out so that the body of the shell may be forced therethrough. The clip is then reformed to-force the tongues formed by the slits down about the cartridge at the bottom of the extraction groove.

Out in the face of the ,breech ,block 36 are a pair of clip. grooves 80 of suitable size and shape to receive aclip 75 which is held therein by a clip retainer. Dovetailed in the block 36 is a feed bar 82 which has three feed dogs placed as shown in Fig. 5 which project from its upper surface and are constructed as shown in Fig. 7. They consist of small bars of hardened steel having an inclined upper face 84: and an engaging face 85. A spring 86 forces them upwardl into notches 87 cut in the edge of the clips 75.

The feed bar 82 is reciprocated across the face of the breech block-36 by means of a cam leverf 90. This lever. is pivoted on a pin 91 secured in the bottom 53 of the frame 31 as best shown in Fig. 4. One end is provided with a slot 92 which engages a pin 93 carried in an opening in the feed bar curved and engaged by a slot formed in t e bottom of the nut 50. The parts are so proportioned that the barrel-in moving forwardfrom the firing position as Shownin Fig. 4 and Fig. '5 holds the cam lever in the position shown in those figures until the barrel is entirely out of the path ofthe cartridges. A fur ther movement of the barrel forward then feeds the feed bar 82 across the breech 36" in the'direction of. the arrows 95*of Fig. 4-and Fig. 5. During the earlypartof the backward movement of the barrel the feed To prevent the overtravel of the clip 7 5 w as it is advanced by the feed bar 82 and to prevent it travelling backward with the feed bar on the return stroke of the bar I provide a clip stop 100. This is in' the form of a flat plate located in slot 102 in the breech block 36 and pivoted on a 'pin'103. The lower end 104 of the stop 100 projects slightly from the breech block near the bottom thereof, as shown in Fig. 2, so that it can be pressed in manually when it is desired to advance a clip with the gun wide open. A small compression. spring 105 holds the stop 100 in its engaging position in which the upper end 106 projects into the path of the clip 75 engaging the slots 87. The upper edge of the feed bar 82 is cut away to forma cam surface 107 as shown in Fig. 4 into which the upper end 106 of thesstop 100 also projects. As the gun starts to close from the position shown in Fig. 4 the feed motion of the feed bar 82 first moves the clip 75 sufliciently to throw the slot 87 away from in front of the end 106 the end 106 being held out of engagement with the slot 87 by the edge of the feed bar 82. As soon as the feed bar has moved the clip 75 a short distance the end 106 is released by the cam surface 107 but cannot move therein due to the fact that it rests against the edge of the lower flange 71 of the clip and slides thereon. As soon, however as the next slot 87 comes along the end 106 springs into it and arrests and stops any further movement of the clip forward and also prevents any backward movement of the clip on the return stroke of the feed bar 82. j

For the purpose of exploding the shells a firing pin 110 is provided which moves in an opening cut in the breech block 36 and which is held in its open position by a small compression spring 111. The firing pin 110 is forced into the primer of the cartridge to be fired by a. firing pin lever 112 pivoted in an open slot in the breech on a pin 113. The lever 112 is engaged at its upper end by a firing rod 114 which is held at its forward end in a guide 115 in which it slides freely.

The rod 114 is held in its forward position by a compression spring 116-. The rod 114 is made of the the nut 50 just before the barrel 35 is fully seated on the shell 74 which isto be fired.

Under some conditions it is desirable to oil the cartridges so that they can, be easily extracted even when under pressure and for this purpose I provide an oiling device 120 which consists of a tube 121 secured to the nut 50 and moving with that nut and conseguently with the barrel. A felt cylinder 122 is placed inside the tube 121 and is kept soaked with oil being filled with oil whenever the gun is oiled. The tube 121 is so 7 spaced with relation to the barrel that it is concentric with one. shell when the shell ahead is in the barrel.

If the gun is allowed. to fire all the shells in any clip it will .fire the last one and then proper length to be struck by close outside the clip and must then be last shell is fired leaving it cooked with a loaded shell ready to fire.

The sear 130 is pivoted on a pin 131 secured in the side 52 of the frame 31 and is provided with a latching notch so placed that it can catch the lower edge of an opening 133 formed in the nut. 50 as shown in Fig. 6. A spring 134 throws the sear 130 into its engaging position and it is held out of its engaging position when there is a clip projecting over its'rear end'which in that case will rest against the clip. The feed bar 82 is cut away as shown in,Fig. 4 at 135 to allow the sear to project under and be held down by the clip 75. As soon as the clip feeds off from the above the rear end of the sear 130 the front end catches the nut 50 stopping the gun, in a cocked position with a loaded shell ready to fire.

- The magazine shown in Figs. 11 and 12 allow a considerable number of shots to be fired without reloading. This magazine consists of a sheet metal box 140 having a tight metal cover 141. The magazine is of sector form as shown. The clips are held in place therein by guide bars 142 and 143.

the arrow 161. A magazine, retainer 164 is also provided to hold the magazines in the magazlne carrier. Y

' The gun shown in Figs. 1 and 2 isprovided with cooling ribs on the barrel and for a light gun that is not to be. fired too often such a method of cooling is entirely adequate. When a gun is desired that will be called on to be fired more often some is desirable. 19 one such method better means of coolin In Figs. 17, 18, an

is shown. In this method cooling ribs are provided which extend longitudinally of the barrel 35 as shown at 200. The barrel 35 with its ribs 200 slides freely in stationary may readily be tubes 201 which are fixed to the frame 31 of the gun and which are connected to a larger tube 202 by connecting washers in air tight relationship. A piston 205 is formed integral-with the barrel 35 and fits tightly in the tube 202 sliding freely therein as the barrel is reciprocate/d. As the cubical eon-- tents of the large tube displaced by the movements of the piston 205 is very much greater than the air space around the barrel between the ribs 200 there results a very rapid and efiicient movement of air around these ribs'as the barrel moves. The air is drawn in at the outer ends of the tubes 201 and expelled therefrom so that the barrel is guite efiiciently cooled.

nother method of cooling the barrel is shown in Figs.'20, 21, and 22. In this method the barrel provided with cooling ribs 200 ismeciprocated inside a stationary tube 301 fixed to'the frame 31 of the gun. The tube 301 is flared out at the muzzle of the gun to form a cylinder 303 in which a piston 304is free to slide. The piston 304 is fru'sto conical in shape and the cylinder 303 is about one half as long as the stroke of the barrel 35. As thebarrel moves forward it pulls fresh air into the spacesaround the ribs 200 and on its return stroke it also forces fresh air obtained by the piston 304 passing out spaces between the r fications of my cooling as for example those in which the barrel would be stationary and the enclosing tubes of the c z linder.v 303 into the s 200. Other modiwould reciprocate.

ward position.

The method of operation of my invention is as follows: The gun is first cocked by grasping the handle 54 and forcing the barrel 35 to its extreme forward position where the nut is caught b the sear 58. A clip can then be inserte in the clip grooves 80 passing in until the stop 100 catches in the first of the slots 87 of the clip 75. The gun is now fired by pulling the trigger which is held down so that as the barrel is forced forward due tothe expansion of gas in the actuator cylinder 39 the sear does not-catch; The barrel is therefore immediately returned by the sprin 56. During the latter part ofthe forwar movement however the clip has been fedforward one cartridge by the dogs 83 of the feed bar 82. the barrel in coming back therefore finds a fresh loaded shell ready for it and the operation is repeated until the clip pulls off from above the end of the sear 130 which then catches and holds the nut 50 'in its for- If a magazine is being used as soon as the h sear 130 it will also pullout from the under magazine so that the magazine will rotate the force of the spring 163 to throw the next clip down against the top of the sear 130'thus releasing the barrel for more firing. As soon as this firing starts the feed bar 82 will reach into the opening 144 of the magazine 140 and start the next clip into the gun. In practice there is a slight stop in the firing while the magazine is shifting but it is hardly noticeable.

system are evident I oilin clip pulls oil from over the The the following explosion of the shell is reduced to a min-- imum.

Second, in a gun havin moves forward from the ring position an actuator which so .moves the barrel.

Third, a magazine in whicha number of short clips may be stored and from which thtiy are Withdrawn in order.

a barrel which urth special forms of clips for the pringfield ammunition.

Fifth, the cylindrical container and the method of packing the special magazines therein.

Sixth, the retarder for slowing down barrel.

Seventh, the new vices.

I claim as my invention- 1. In a gun, the combination of: a moving barrel; means for inserting cartridges in said barrel; and an oiling device actuated by said barrel lubricating the exterior of said cartridges before they are place-d in said barrel.

2. In a gun, the combination of: a barrel member; a breech member, said breech member being fixed and said barrel member being movable with relation thereto; and means carried on one of said members forlubricating a cartridge stationary with relation to the other member.

the

forms of air cooling de- 3. In a gun,-the combination of: a barrel member; a breech member, said breech member being fixed and said barrel member being movable with relation thereto; and an device fixedto said barreLin sucha position as to lubricate the exterior of the cartridges used in said n before said cartridges are placed in sai barrel.

4. In a gun, the combination of: a barrel member; a breech member, said breech member-being fixed and said barrel member being movable with relation thereto; and an oiling receiver fixed to said barrel, in which the cartridges are inserted before being inserted in the barrel.

In'testimony whereof, I have hereunto set my hand at Springfield, Massachusetts, this 29th day of August, 1917.

BURLEIGH PUTNAM. 

